Off-shore platform construction, and method for transferring loads

Abstract

A method is described for using a particular spring element to facilitate the transfer of deck modules to a hull or jacket during the construction of an off-shore well platform. The spring element not only absorbs energy from the compressive loading expected during the transfer, but also resists any shear loading caused by relative motion between the module and the jacket or hull caused by the operation being performed in a body of water. The spring element includes two significantly different resistances to crushing when subjected to compressive loading including an initial resistance during which significant energy is absorbed. The spring element is also provided on the carrier barge between the barge and the deck module so that if the carrier barge should reengage the module once the transfer has been started, damage will be inhibited.

What is claimed is: 
     
       1. In a method of transferring a load from a carrying article to an object when it is believed there may be relative movement between the article and said object during the transfer, the steps of: selecting a spring element capable of resisting shear loading and having a relatively constant capability of accepting compressive loading over a significant range of the deflection expected during said transfer, said spring element being made up of a plurality of struts of elastomeric material which are individually configured to respond to compressive loading by buckling in a predetermined direction;   positioning said selected spring element at a location at which said load is to contact said object during said transfer; and   using said spring element during said transfer to engage said object.   
     
     
       2. The method of claim 1 wherein said step of positioning includes positioning a plurality of said selected spring elements at a respective plurality of spaced locations at which said load is to contact said object during said transfer. 
     
     
       3. The method of claim 1 wherein said step of selecting includes selecting a spring element for said positioning having sufficient creep to provide direct contact between said load and the object to which it is transferred after such transfer. 
     
     
       4. The method of claim 1 further including the step prior to said step of using, of positioning selected spring elements on said article at one or more locations at which said load may engage said article during said transfer. 
     
     
       5. The method of claim 1 wherein a plurality of said spring elements are selected, and said step of positioning includes positioning each of said spring elements with its struts oriented relative to those of other spring elements to buckle in one or more materially different directions. 
     
     
       6. In a method of constructing a platform for use at a location within a body of water to extract a flowable substance from the earth beneath said body of water, the steps of: (A) providing a support structure for a deck component of said platform, which support structure includes at least one tower for supporting said deck component at a particular location relative to the surface of said water body;   (B) selecting a spring element capable of resisting shear loading and having a relatively constant capability of accepting compressive loading over a significant range of deflection, said spring element being made up of a plurality of struts of elastomeric material which are individually configured to respond to compressive loading by buckling in a predetermined direction;   (C) positioning said selected spring element at a location on said tower at which said deck component is to be engaged by said tower during transfer of said component to said tower;   (D) positioning adjacent said tower in said body of water, a carrier having said deck component; and   (E) using said spring element during said transfer of said deck component from said carrier to said tower at the location of said spring element to absorb energy caused by movement of said component between said carrier and said tower.   
     
     
       7. The method of claim 6 wherein said step of positioning a carrier adjacent said tower includes floating said carrier on said body of water. 
     
     
       8. The method of claim 6 wherein said step of positioning said selected spring element includes positioning a plurality of said selected spring elements at a respective plurality of spaced locations at which said component is to contact said support structure during said transfer. 
     
     
       9. The method of claim 6 wherein said step of selecting includes selecting a spring element for said positioning having sufficient creep to provide direct contact between said component and said support structures after said transfer. 
     
     
       10. The method of claim 6 wherein said step of selecting includes selecting a plurality of said spring elements, and said step of positioning includes positioning said individual elements with the struts of at least some of said elements oriented relative to those of other elements to buckle in one or more materially different directions. 
     
     
       11. The method of claim 6 further including prior to said step of using, of positioning another selected spring element on said carrier at a location at which said deck component is supported during said transfer. 
     
     
       12. In a method of constructing a platform for use at a location within a body of water to extract a flowable substance from the earth beneath said body of water, the steps of: (A) providing a support structure for a deck component of said platform, which support structure includes at least one tower for supporting said deck component at a particular location relative to the surface of said water body;   (B) positioning a selected spring element at a location on said tower at which said deck component is to be contacted by said tower during transfer of said component to said tower, said selected spring element having a relatively constant capability of accepting compressive loading over a significant range of the deflection that is expected and being made up of a plurality of struts of elastomeric material which are individually configured to respond to compressive loading by buckling in a predetermined direction;   (C) positioning adjacent said tower in said body of water, a carrier having said deck component;   (D) positioning another spring element on said carrier at a location at which said deck component is supported during said transfer; and   (E) using said spring elements during said transfer of said deck component from said carrier to said tower.   
     
     
       13. The method of claim 12 wherein said step of positioning a carrier adjacent said tower includes floating said carrier on said body of water. 
     
     
       14. The method of claim 12 wherein said step of positioning a selected spring element includes positioning a plurality of said selected spring elements at a respective plurality of spaced locations at which said component is to contact said support structure during said transfer. 
     
     
       15. The method of claim 12 wherein said step of selecting includes selecting a spring element for said positioning having sufficient creep to provide direct contact between said component and said tower after said transfer. 
     
     
       16. The method of claim 12 wherein said step of positioning a selected spring element includes selecting a plurality of said spring elements, and positioning the individual elements with the struts of each element oriented relative to those of other elements to buckle in one or more materially different directions. 
     
     
       17. The method of claim 12 further including prior to said step of using, of positioning another selected spring element on said carrier at a location at which said deck component is supported during said transfer. 
     
     
       18. In a method of transferring a load between a pair of structures in a body of water, at least one of which is floating during the transfer, comprising the steps of: (A) selecting a spring element capable of resisting shear loading and having a relatively constant capability of accepting compressive loading over a significant range of expected deflection, said spring element being made up of a plurality of struts of elastomeric material which are individually configured to respond to compressive loading by buckling in a predetermined direction;   (B) positioning said selected spring element on the one of said structures to which said load is to be transferred at a location at which said load is to contact said structure during said transfer; and   (C) using said spring element for said transfer to absorb energy caused by relative movement between said structures, including energy caused because at least one of said structures is floating on said body of water.   
     
     
       19. The method of claim 18 wherein said step of positioning said selected spring element includes positioning a plurality of said selected spring elements at a respective plurality of locations at which said component is to contact said support structure during said transfer. 
     
     
       20. The method of claim 18 wherein said step of positioning said selected spring element includes selecting a spring element for said positioning having sufficient creep to provide direct contact between said component and said tower after said transfer. 
     
     
       21. The method of claim 18 further wherein said step of positioning said selected spring element includes selecting a spring element having a relatively constant capability of accepting compressive loading over a significant range of expected deflection. 
     
     
       22. The method of claim 18 wherein there are a plurality of said spring elements and struts of said spring elements are oriented relative to one another to buckle in materially different directions. 
     
     
       23. The method of claim 18 further including prior to said step of using, of positioning another selected spring element on said carrier at a location at which said deck component is supported during said transfer. 
     
     
       24. A method of constructing a platform for use at a location within a body of water to extract a flowable substance from the earth beneath said body of water, the steps of: (A) providing a support structure for a deck component of said platform, which support structure includes at least one tower for supporting said deck component at a particular location relative to the surface of said body of water;   (B) providing a plurality of springs, each of which is made up of a plurality of spring elements having a pair of opposed and spaced generally parallel support plates between which a plurality of chevron-shaped struts extend, at least two struts of each spring element being oriented in opposite directions;   (C) positioning said springs at locations on said support structure at which said support structure is to be engaged by said deck component during transfer of said component to the same;   (D) positioning a plurality of springs on a carrier for said deck component at locations at which said deck component is supported during said transfer;   (E) positioning said carrier adjacent said tower in said body of water; and   (F) using said springs during said transfer of said deck component from said carrier to said support structure to absorb energy caused by movement of said component between said carrier and said support structure.   
     
     
       25. The method of claim 24 wherein said step of providing springs made up of a plurality of spring elements having struts extending between the plates, includes providing such springs in which each strut includes a notch which aids in directing buckling of the strut in a predetermined direction.